This invention relates to a process for the preparation of aromatic substances which can be employed as aromatizing additives for tobacco.
It is known that fresh tobacco plants contain diverse natural substances which, as smoke aroma precursors, influence the tobacco aroma. Thus, the surface resin of fresh tobacco plants, obtained by brief "washing" of the plants, contains the diterpenes, especially duvanes, which are valuable as precursors. The procedure for separating off these diterpenes has been disclosed in German Offenlegungsschrift No. 2,918,920. The diterpene fractions obtained by this procedure can, after isolation and purification, be added to conditioned tobacco (tobacco which has been processed ready for use).
Carotenoids which are also aroma precursors, also occur in the tobacco plants themselves. The isolation of these carotenoids in the form of alcoholic extracts is also known.